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Symptoms of E. coli: How to Know if You Have an Infection, and What Type

The symptoms of an E. coli infection vary, depending on where the infection is — and who’s sick.

E. coli bacteria is responsible for more than 85 percent of urinary tract infections.

Escherichia coli, or E. coli, is best known as the bacteria that can cause outbreaks of foodborne intestinal infections (think: food poisoning and traveler’s diarrhea). But pathogenic E. coli can also lead to a number of other illnesses outside of the digestive tract.

Naturally, the symptoms you experience from an E. coli infection depend on what kind of infection occurs — and where in the body the infection is concentrated. (1)Here are the most common E. coli infections and their associated symptoms:

Intestinal E. coli Infection Symptoms

There are numerous types of E. coli bacteria that can cause food poisoning. While each bring about similar symptoms, there are slight variations.

Enterotoxigenic E. coli This uses hair-like appendages to attach to the intestine and attacks the body with toxins. These bacteria are often the cause of traveler’s diarrhea. There is no fever associated with this E. coli infection. (2)

Enteroinvasive E. coliThis is a type that invades the cells lining the colon and results in diarrhea with fever, according to a paper published in December 2017 in the journal Frontiers in Microbiology. (3)

Enteropathogenic E. coli This attaches to intestinal cells using a special protein. It’s a common culprit of infantile diarrhea in developing countries. This particular type of E. coli infection causes watery and sometimes bloody diarrhea, according to research. (4)

Shiga Toxin–Producing E. coli (STEC) STEC is the type most commonly heard about on the news because of the outbreaks it causes. An intestinal infection by STEC — which typically lives in cattle and migrates to humans after animal feces contaminate human food — results in:

Editor’s Picks on Conditions Related to Intestinal E. coli Infections

Complications Associated With Intestinal E. coli Infections

Approximately 5 to 10 percent of individuals with STEC develop a related complication called hemolytic uremic syndrome (HUS). This is a potentially life-threatening condition where the red blood cells that have been destroyed by the E. coli bacteria go on to damage the kidneys’ filtering system, which can lead to kidney failure.

Those who are most likely to be impacted include children under age 5, the elderly, and those with compromised or weakened immune systems. (6) People who take antibiotics to treat an E. coli infection are also at an increased risk for developing HUS, according to a report published in November 2012 in the journal Toxins. (7)

Usually, HUS emerges about seven days after E. coli symptoms first appear — and once diarrhea starts to subside. (6)

It’s very important to immediately visit a healthcare professional if the affected individual doesn't urinate for 12 hours or more, experiences bloody diarrhea, or has several days of nonbloody diarrhea followed by:

Decreased urine output

Unexplained bruising

Unusual bleeding (8)

Symptoms of E. coli Infections in the Urinary Tract

The E. coli bacteria is behind more than 85 percent of all urinary tract infections (UTIs), according to research published in March 2012 in the journal Emerging Infectious Diseases. (9)

UTIs occur when E. coli, which typically resides in the colon, enters the urinary system through the urethra. This can happen through improper hygiene (wiping from back to front after a bowel movement) or via sexual contact. A woman’s urethra is located next to the vagina and anus, making for an easy pathway for E. coli to enter the urinary tract. (10)

Urinary tract infections don't always produce symptoms, but most people will experience at least one of the following signs:

Symptoms of E. coli Infections That Cause Neonatal Meningitis

It’s estimated that E. coli causes about 20 percent of all neonatal bacterial meningitis cases, but less than 2 percent of meningitis cases at all other ages. (11) Premature babies and those born at a low birth weight are at an increased risk of contracting this type of meningitis. An E. coli strain called K1 causes the vast majority of all E. coli–related neonatal meningitis cases, according to the Meningitis Research Foundation. (11) Newborns may become infected with E. coli K1 during birth, or from bacteria later acquired in the hospital or home. That said, bacterial meningitis is very rare in developed countries.

A newborn with meningitis may experience one or more of the following symptoms:

Older children or adults with bacterial meningitis due to E. coli usually develop a stiff neck and have a headache as well. (12)

Symptoms of E. coli Infections That Cause Sepsis

Beyond neonatal meningitis, E. coli (as well as listeria and certain strains of streptococcus) can also put newborns and babies at risk for sepsis, or blood poisoning. Neonatal sepsis is an infection of the blood that occurs in babies less than 90 days old. The infection can be acquired from the mother before or during delivery (preterm delivery, early water breaking, and chorioamnionitis increase risk), or after delivery due to an extended hospital stay or extended catheter use. Signs and symptoms include:

Neonatal sepsis is a serious issue and a leading cause of infant death. The more quickly an infant gets diagnosed and treated with antibiotics, the better the outcome. (13)

Symptoms of E. coli Infections That Cause Pneumonia

Streptococcus pneumoniae is the most common bacterial perpetrator of pneumonia, but E. coli can also sometimes cause the disease, according to the Centers for Disease Control and Prevention (CDC). (14) The most common symptoms of pneumonia include:

Chest pain when breathing or coughing

Cough with phlegm

Shortness of breath

Nausea, vomiting, or diarrhea

Fatigue

Fever

Shaking chills

Confusion or changes in mental awareness (in those ages 65 and older)

Lower than normal body temperature (in those ages 65 and older and in people with a weakened immune system) (15)

Additional reporting by Joseph Bennington-Castro.

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